Object-Based Audio Loudness Compensation for Flexible Decoder Rendering

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Solution Overview

Problem

Current audio rendering technologies face challenges in maintaining consistent loudness across different audio programs and channels, leading to annoying volume fluctuations, especially when switching between programs or channels, due to differences in perceived loudness despite normalized peak signal levels, which existing solutions fail to address effectively on the decoder side.

Innovation Solution

A decoder and encoder system that estimates loudness using object-based audio coding, providing loudness information to the decoder to compensate for rendering changes, ensuring consistent loudness by determining a loudness compensation value based on received loudness and rendering information, allowing for accurate and immediate loudness adjustment without delay.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If audio rendering is conducted on the decoder side to enable flexible audio object manipulation, then adaptability and ease of operation are improved, but loudness consistency deteriorates due to significant effects on overall/total loudness

Engineering Contradiction:

Improveaudio rendering flexibilityVSAvoidloudness consistency

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The encoder performs preliminary loudness estimation and transmits loudness information to the decoder before rendering occurs. This allows the decoder to pre-calculate compensation values and maintain loudness consistency while still enabling flexible rendering operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where loudness information from the encoded audio objects is used by the decoder to adjust rendering parameters. The decoder calculates compensation based on transmitted loudness data and applies it during rendering to maintain consistent overall loudness despite flexible object manipulation.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If signal-based loudness estimation is performed in the decoder to ensure accurate loudness measurement, then measurement precision is improved, but processing time and complexity increase

Engineering Contradiction:

Improveloudness estimation accuracyVSAvoidprocessing delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Instead of performing full signal-based loudness estimation in the decoder, the system uses copied loudness information that was pre-calculated and transmitted by the encoder. This copying approach maintains measurement precision while dramatically reducing processing time and complexity in the decoder.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The loudness estimation is performed in advance during encoding, and the results are transmitted to the decoder. This preliminary action eliminates the need for time-consuming loudness calculations in the decoder, reducing processing delay while maintaining accuracy.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If parametric techniques are used for bitrate-efficient transmission of audio scenes, then transmission efficiency is improved, but loudness information completeness deteriorates

Engineering Contradiction:

Improvebitrate efficiencyVSAvoidloudness information

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The system extracts and transmits only the essential loudness information needed for compensation, separate from the full audio object data. This extraction approach maintains bitrate efficiency while ensuring that sufficient loudness information is available for accurate compensation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Loudness information serves as an intermediary element that bridges the parametric encoding efficiency and the need for accurate loudness measurement. By transmitting this intermediate loudness data, the system enables both efficient compression and accurate loudness control without requiring full signal transmission.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2941771B1Decoder, encoder and method for informed loudness estimation employing by-pass audio object signals in object-based audio coding systems

Publication Date: 2017.03.29 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV

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AI summary

A decoder for generating an audio output signal comprising one or more audio output channels is provided. The decoder comprises a receiving interface (110) for receiving an audio input signal comprising a plurality of audio object signals, for receiving loudness information on the audio object signals, and for receiving rendering information indicating whether one or more of the audio object signals shall be amplified or attenuated. Moreover, the decoder comprises a signal processor (120) for generating the one or more audio output channels of the audio output signal. The signal processor (120) is configured to determine a loudness compensation value depending on the loudness information and depending on the rendering information. Furthermore, the signal processor (120) is configured to generate the one or more audio output channels of the audio output signal from the audio input signal depending on the rendering information and depending on the loudness compensation value. One or more by-pass audio object signals are employed for generating the audio output signal Moreover, an encoder is provided.